In the field of data transmissions, the data may be marred by errors due to the transmission channel itself. Transmission in wireless channels, such as for example the use of UMTS (Universal Mobile Telecommunication System), WiFi technology, or else WiMAX, or the solutions employed on High Frequency (HF) channels etc. gives rise to errors which may disturb the decoding of the data on reception.
To combat the risk that these errors may disturb transmission, it is known to a person skilled in the art to use solutions of data retransmission type, for example, the technique of automatic retransmission of data better known by the abbreviation ARQ (Automatic Request), or its offshoot hybrid-ARQ. These solutions are in general applied at the network level.
There also exist solutions relying on the introduction of redundancy (FEC: Forward Error Correction) at the radio access level, that is to say at the level of the physical layer of the transmission system directly.
It is also known to employ standard compressed headers with a more significant error corrector coding at the level of the physical layer or the use of retransmissions.
The main drawback of the solutions present in the state of the art is that, in general, the protection is afforded at the level of the header plus data as a whole, without differentiation and with deletion of the packet in the case of corruption, whereas one might possibly wish to receive partially corrupted payloads if in fact their header remains correct.
An additional drawback to retransmission techniques is that they assume the presence of a duplex link, this not always being possible, notably in the case of broadcasting applications.
Another drawback of the prior art techniques is that they give rise to a high level of redundancy at the physical level, under the network layer. This can cause on the one hand, an incompatibility with the standard used (if no provision has been made for such a protection level, or the use of the codes that one wishes to use) and on the other hand, generally leads to an increase in the protection level on the packet as a whole in an undifferentiated manner, thus turning out to be more expensive in terms of bandwidth.
The idea of the invention relies on a new approach which consists notably in protecting the header of the packet to be transmitted without this involving also protecting the useful data in the event that the data transmission is operating normally.